clean up test output

- removed a few remaing places where output wasn't being passed
  through echo_i or cat_i
- added a "digcomp" function to conf.sh.in to send digcomp.pl output
  through cat_i and return the correct exit value
- set SYSTESTDIR when calling echo_i from nsX directories, so that
  the test name will always be printed correctly
- fixed a test name typo in conf.sh.in

bin/tests/system/masterformat/tests.sh

@@ -91,10 +91,10 @@ for zone in example example-explicit example-compat; do
 		echo
 	done > dig.out.$zone.$server
     done
-    $PERL ../digcomp.pl dig.out.$zone.1 dig.out.$zone.2 || ret=1
+    digcomp dig.out.$zone.1 dig.out.$zone.2 || ret=1
     if [ $zone = "example" ]; then
-            set -- 1 2
-            $PERL ../digcomp.pl dig.out.$zone.1 dig.out.$zone.3 || ret=1
+        set -- 1 2
+        digcomp dig.out.$zone.1 dig.out.$zone.3 || ret=1
     fi
 done
 [ $ret -eq 0 ] || echo_i "failed"